1. Field of the Invention
The present invention relates to systems and methods for recovering cellulosic fiber from waste products such as landfill materials, e.g., post-consumer, municipal, and industrial waste materials, and to systems and methods for removing and recovering adverse inorganic chemicals and materials from such products in order to produce cellulosic thermal insulation with certain performance and ash content characteristics, as well as to produce material used in fowl and animal bedding with certain desirable characteristics and filler materials for various organic and inorganic compositions.
2. Related Art
A widely used insulating material for homes and other buildings is commonly manufactured by fiberizing waste (primarily clean recycled newsprint; commonly referred to as “old newsprint” or “ONP”) that has few contaminates (such as plastic, string, metal foil and glass), in suitable equipment (such as a hammer mill or a disc refiner), while adding dry fire retardant chemicals (such as boric acid and ammonium sulfate).
Cellulose insulation has been produced using a variety of manufacturing equipment for approximately 80 years. Methodology has only varied slightly over the years using a combination of paper shredders, hammer-mills with sizing screens and disc refiners to produce a market acceptable product.
The quality of cellulose insulation is defined technically as compliance with the industry standard ASTM C739. Products are labeled with testing results; normally from a third party testing facility, and certain components are tested regularly by manufacturers for quality assurance. The attributes traditionally tested in-house by manufacturers include two fire resistance tests; radiant panel and smoldering combustion, pH to confirm fire retardant chemical formulation and settled density.
Customers assume compliance with ASTM C739; however consider a quality product as one that provides the coverage per package that is advertised (product density and package weight), product texture or particle size, amount of contaminants and dust level.
Product coverage dictates the economic impact to the customer of using the product. The product density is an important indicator of a product's eventual coverage. A product's density is impacted by the fiber quality of the ONP, the condition of wear surfaces in the disc refiner and chemical content. Particle size is dictated by the condition of wear surfaces in the disc refiner and the gap settings within the refiner. Contaminants are a factor of the quality of the ONP and minimal process separation devices. Dust levels are dictated by the quality of ONP, wear surface condition in the disc refiner, chemical content and level of inorganic components from the ONP source.
In recent years it has become more difficult to obtain clean waste newsprint at acceptable prices in order to manufacture cellulosic insulation using the common dry manufacturing process mentioned above (which process is currently utilized by the entire U.S. cellulosic insulation market). There are numerous less expensive cellulosic fiber sources available today that all have non-desirable compositions or are mixed with non-desirable materials that cannot be used to manufacture cellulosic insulation utilizing the traditional dry production process to produce cellulosic insulation that meets Federal Specification requirements (including those by the U.S. Consumer Product Safety Commission and Federal Specifications such as ASTM C739-91, ASTM C739-03, ASTM E970, ASTM C518, ASTM C1148, ASTM D778 and HH-I-515D). In addition, the cost of clean dry waste newsprint has risen to levels that make it difficult to economically and competitively manufacture acceptable cellulosic insulation. This is due to the increase in demand for clean recycled newsprint, primarily from Asia.
Modern conventional processes require the use of #8 or #9 old newspapers (ONP) that are considered a high grade of recycled fiber. The entire process requires the use of dry ONP that has minimal contaminants (plastic, metal waste, etc). ONP is metered through a primary shredder, through a secondary hammer-mill and then a disc refiner to create the finished product. Fire retardant chemicals are metered through a pulverizer and added to the process normally before the disc refiner.
The most significant challenge facing conventional processes is the quality and composition of ONP. Papermaking technology has advanced to using recycled ONP as the primary source of fiber rather than virgin sources (trees). The addition of various fillers (primarily calcium carbonate; CaCO3) has caused difficulty for cellulose insulation manufacturers to maintain good (lower) densities and a low-dust level product. The measurement of a product's thermal performance (R-value) is hindered by high densities and high levels of inorganic particles. Additionally, the advent of single-stream recycling programs has significantly reduced the availability of high quality ONP, one that is virtually free of contaminants and is dry.
Attempts to utilize a wet process to separate cellulosic fibers from contaminates found with or adhering to the cellulosic fibers have been made in the past. The common approach has been to utilize a standard hydro-pulping device to separate the cellulosic fibers from the contaminates, utilizing a harsh mechanical process that also degrades the fibers and leaves the contaminates in very small pieces that are difficult or impossible to remove. This method has not proven to be successful commercially to produce a cellulose based fiber insulation.
There are many types of waste materials that contain cellulosic fibers that cannot be recycled in conventional processes and are sent to landfills because the fibers are either (i) laminated and contain layers of plastic or metal foil (such as milk cartons and industrial scrap from aluminum roll boxes), and/or (ii) mixed with plastics, metal and/or glass to such a degree that it cannot be used. In addition, current papermaking research is directed to increasing the calcium carbonate loading, from approximately 5 to 7%, to a much higher 15 to 20% loading by reacting in situ calcium carbonate not only on the surface of the fibers but also in the hollow spaces within the fibers.
Paper manufacturers continue to increase the use of calcium carbonate as a major component in their papermaking processes to facilitate the use of greater amounts of shorter recycled fibers and thereby retain the desired sheet strength and other desirable physical properties. It should be noted that typical waste paper recycling processes, by design, retain these fillers as a necessary component to retain the physical properties of recycled paper stock. However, it is desirable to remove these fillers in order to produce acceptable products for uses other than the recycling of waste paper back into reconstituted (recycled) paper stock. Current levels of calcium carbonate and other fillers along with the increasing use of short fibers (fines) in the recycled waste paper stream is presenting a major problem for dry process cellulosic insulation manufacturers today. Products increasingly have a higher nuisance dust content, have higher bulk densities, and lower heat loss resistance values.
In order for a quality cellulosic thermal insulation to be manufactured with today's recoverable waste paper and fiber sources, the greater portion of the calcium carbonate's and other fillers should be removed, for example, by dissolving the calcium carbonate from within and on the fiber surfaces, and then precipitate and remove this contaminant and other fillers. The manufacture of quality cellulosic thermal insulation will become increasingly more difficult using the processes and technologies that are available today.
There have been several attempts to produce cellulosic insulation from waste fibers using systems that utilize a combination of wet and dry process steps. For example, U.S. Pat. No. 6,155,020, to Deem, issued Dec. 5, 2000, discloses a method for producing insulation out of recycled carpet utilizing a dry shredding process to separate the useful fibers from the carpet backing and other non-used materials.
U.S. Pat. No. 5,714,040, to Poy et al., issued Feb. 3, 1998, discloses a method for recovering fiber from printed newspaper by loading the waste paper and water into a continuous batch fiber recovery apparatus. All are agitated within the apparatus to form a pulp fiber slurry while introducing de-inking and agglomerating compositions to causes ink particles associated with the printed newspaper to separate. These ink particles are then removed from the pulp using separation techniques.
U.S. Pat. No. 5,272,852, to Fortin et al., issued Dec. 28, 1993, discloses a process where an insulating pulp is formed from debarked trees, primarily black spruce, using a chemi-thermo-mechanical pulping process to make a fluffed form or to form a compressed sheet that is later defiberized utilizing a portable insulating pulp applicator. The resulting product has a fire retardant additive in the range of 10%-25% by weight.
U.S. Pat. No. 5,084,307, to Nishimoto et al., issued Jan. 28, 1992, discloses a flame retardant vegetable fiber material and a process for the production of this material. Vegetable fiber is immersed into two inorganic solutions to fill the inherent gaps of the fiber to create an insoluble and incombustible inorganic compound that can be used as a fire retardant material such as asbestos or rock wool. The inorganic solutions utilized include first, magnesium chloride, barium chloride, calcium carbonate, aluminum chloride, aluminum borate and aluminum sulfate and second, ammonium sulfate, ammonium pyrophosphate, ammonium magnesia and boric acid soda.
U.S. Pat. No. 4,454,992, to Draganov, issued Jun. 19, 1984, discloses a combination wet/dry system that utilizes an aqueous solution of non-hydroscopic fire retardants to produce cellulosic insulation. The process described uses a predominately dry process to grind shredded newsprint and add fire retardant chemicals in a wet form with elevated temperature to utilize a low amount of fire retardant chemicals to meet commercial fire retardancy requirements.
There also have been attempts to produce non-insulation products from waste fibers that focus on separating the fibers from non-fibrous materials. For example, U.S. Pat. No. 4,737,238, to de Ruvo, et al., issued Apr. 12, 1988, discloses a process for treating waste paper containing aluminum and having high lignin content by de-lignifying and pulping the waste paper for reuse in papermaking.
U.S. Pat. No. 4,760,717, to Ponzielli, issued Aug. 2, 1998, discloses a process that uses a hydro-pulping like apparatus to separate plastic film from cellulosic fibers goods. This process acts like a blender to shred the materials during processing.
U.S. Pat. No. 6,238,516, to Watson et al., issued May 29, 2001, discloses a system and process whereby pulping machines are utilized to recycle plastic and cellulosic fibers from disposed diapers. The process utilizes a similar fiber recovery apparatus to separate the plastic from the cellulosic fibers, then clean the plastic and cellulosic fibers from all waste material for further use.
Despite these known approaches, and the increasing need for quality waste products, no commercial process has been developed to produce cellulosic insulation out of waste paper materials that are contaminated with a high degree of calcium carbonate, fines, and other non-organic materials (such as plastics, foils, glass, metal and other non-organic content), and materials that are contained in, commingled with, or laminated to the cellulosic fibers or waste fibers. These waste materials are currently sent to a landfill and landfills are becoming increasingly scarce and difficult to build.
In regard to animal and fowl bedding materials, conventional paper-based bedding frequently contains contaminants that are a result of poor quality old newspapers. Since the animals frequently ingest the bedding, some of these contaminants can cause illness and therefore growth issues with the animals. Mold and bacteria are a significant problem with conventional wood shavings or sawdust. These also are supplied with widely varying levels of moisture.
Conventional paper-based bedding has previously been supplied either as chips of paper or as fiber. These tend to not be as absorbent and compact tightly minimizing the thermal advantages. Customers will endeavor to reconstitute or fluff up their bedding to allow it to dry and gain additional life from the bedding. Conventional paper-based bedding is produced in a dry process using various shredders and hammer-mills, thus making the addition of additives that adequately adhere to the fibers difficult or inefficient.
Conventional paper-based bedding is produced using ONP and other common recycled paper based products. Conventional processes do not have the capability of managing and therefore reducing the inorganic components of the raw material. Inorganic particles add to the dust level of the finished product, add no absorption qualities and aid in the compaction issues inherent with paper-based bedding.
There are several purposes for providing animal and fowl bedding: animal and fowl bedding absorbs excess moisture from the droppings and drinkers and promotes drying by increasing the surface area of the house floor; animal and fowl bedding dilutes fecal material, thus reducing contact between birds and manure; and in the poultry industry, animal and fowl bedding insulates chicks from the cooling effects of the ground and provides a protective cushion between the birds and the floor.
An effective bedding material must be absorbent, lightweight, inexpensive and non-toxic. Ideal materials will have high moisture absorption and release qualities to minimize litter caking. In addition, a bedding material must be compatible as a fertilizer or soil amendment or for incineration after it has served its purpose in the poultry house.
Excess moisture in the litter increases the incidence of breast blisters, skin burns, scabby areas, bruising, condemnations and downgrades. The wetter the litter, the more likely it will promote the proliferation of pathogenic bacteria and molds. Wet litter is also the primary cause of ammonia emissions, one of the most serious performance and environmental factors affecting broiler production today. Controlling litter moisture is the most important step in avoiding ammonia problems.
Conventional animal and fowl bedding products have significant disadvantages, as Table I indicates:
TABLE IAdvantages and Disadvantages of VariousAnimal and Fowl Bedding MaterialsPine shavingsPreferred litter material but becoming limitedand sawdustin supply and expensive in areas.Hardwood shavingsOften high in moisture and susceptible toand sawdustdangerous mold growth if stored improperlyprior to use.Pine orUsed successfully but may cause increasedhardwood chipsincidence of breast blisters if allowed tobecome too wet.Pine orSimilar to chips or shavings in moisturehardwood barkabsorption capacity. Medium-sized particlespreferred.Rice hullsA good litter material where available at acompetitive price. Young chicks may beprone to litter eating (not a serious problem).Peanut hullsAn inexpensive litter material in peanut-producing areas. Tends to cake and crust butcan be managed. Susceptible to mold growthand increased incidence of aspergillosis.Some problems with pesticides have beennoted in the past.SandField trials show comparable performance topine shavings. Long-term reuse potentialwith de-caking. More difficult to maintainsuitable floor temperatures during coldweather brooding. Need ample time andventilation prior to brooding to assuredryness.Crushed corn cobsLimited availability. May be associated withincreased breast blisters.Chopped straw,Considerable tendency toward caking. Moldhay or corn stovergrowth can also be a disadvantage.Processed paperVarious forms of processed paper haveproven to be good litter material in researchand commercial situations. Tendency to cakewith increased particle size. Top dressingpaper base with shavings may minimize thisproblem.
Despite these known animal and fowl bedding products, and the increasing need for a high quality, inexpensive and widely available product, limited commercial products or processes have been developed to meet the needs of private and commercial animal owners for animal and fowl bedding. These needs include: (a) a higher degree of absorbency than sawdust, straw or wood shavings; (b) a higher degree of absorbency than conventional paper-based bedding; (c) a consistently manufactured product; (d) a uniform particle size and composition; (e) a product that maintains its uniform particle size and composition without severe compaction; (f) improved thermal qualities; and (g) relatively quick decomposition following disposal. Furthermore, consumer and commercial users of animal and fowl bedding would greatly appreciate animal and fowl bedding that is virtually free from contamination, can be custom manufactured to include performance enhancers, is delivered with consistent moisture content levels, that can be purchased in packages that are relatively clean and easy to store, and which can be used for biomass power generation in a manner that is safe for the environment.